If you've come to this review looking for answers then you're out of luck. All I know is I just watched SUICIDE CIRCLE and NORIKO'S DINNER TABLE back to back and it was great! But I still don't have any answers for you.
One evening at 7:30 54 teenage girls lined up side-by-side at a subway station and jumped in front of an oncoming train. The only clue the police find is a white sports bag with a coiled up "chain" of human skin inside it. There's also a mysterious website with dots that always appear right before the suicides happen. That's about it. The rest of the movie is just a series of suicides and the police investigating them. No real concrete answers are ever given, but that doesn't mean you won't enjoy the film. I thought the first hour was a blast, but then around the 61 minute mark things start falling apart and just getting confusing as shit until the movie abruptly ends.
The story might be confusing, but I have to hand it to director/writer Shion Sono he really knows how to set up the creepy mood and make even a movie with no real plot fun to watch. Check it out!